In the processes for manufacturing semiconductors, for example, there is a conveying process which takes out in a horizontal direction a semiconductor wafer of a thin circular plate stored in a cassette (FOUP) under a state of horizontal posture, and conveys the semiconductor wafer to another spot where a predetermined process is applied to the semiconductor wafer.
A device for conveying a substrate, such as this semiconductor wafer, is disclosed in Patent Document 1 to be known. In this device, an arm is provided to a case so as to be rotatable in a horizontal plane, and a hand, on which a substrate is placed, is provided to the distal end portion of this arm. A motor as a driving source is disposed in the case, and from the motor to the hand, power transmitting members, such as a pulley and a belt, are disposed in a horizontal direction in multiple stages. Therefore, the distance from the motor to the hand in the horizontal plane is long. The power transmitting members are sealingly stored in the case and the hand.
When power is transmitted from the motor to the hand, the power transmitting members may rub each other so as to cause particles, such as powder dusts. However, the power transmitting members are sealingly stored in the hand, the particles are prevented from scattering from the inside of the case or the hand so that the particles do not adhere to the plate member.
On the other hand, Patent Document 2 discloses a conveyance device provided with a plurality of substrate holding members of plate shape which are disposed in the vertical direction with intervals, the intervals being able to be changed. A plurality of substrates are stored in a cassette with intervals in the vertical direction, and when the plurality of substrates are conveyed from the cassette to another spot, their vertical pitch may be changed. Therefore, according to this conveyance device, a plurality of substrates can be conveyed with their pitch coverted.